ELFT HÍRADÓ

[StatFizSzeminar <statfiz AT glu.elte.hu>]

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                   ELTE Institute of Physics
                SEMINARS IN STATISTICAL PHYSICS


                        9 September 2015
                       Wednesday, 11 a.m.

                         Ulrike Feudel

 Institute for Chemistry and Biology of the Marine Environment,
 Carl von Ossietzky University of Oldenburg, Oldenburg, Germany

             "Extreme events in excitable systems"


We consider the dynamics of rare events at which an observable of a complex
dynamical system is extreme in amplitude. Since our goal is to contribute to 
the
understanding of the emergence and the termination of epileptic seizures and 
of
harmful algal blooms, we focus on excitable systems, which are useful models 
to
describe those two phenomena. Therefore, we study deterministic networks of
excitable elements of FitzHugh--Nagumo type. We demonstrate that these 
networks
are capable of self-generating such events at irregular times, i.e., without a
change of control parameters or without an input to the system. To get a 
better
understanding of this behavior, we study a reduced system consisting of two
coupled FitzHugh--Nagumo oscillators which mimics the extreme-event dynamics
observed for the networks. We discuss the properties of the networks as well 
as
of the reduced system that may be involved in the generation and termination 
of
such extreme events. Finally we discuss the dynamics involving extreme events
for different network topologies such as complete graphs and small world
networks.


                          Room 2.54
     1117 Budapest, Pázmány P. sétány 1/A (Northern Block)
              home page: http://glu.elte.hu/~statfiz


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